Crooks claiming to have hacked television group HBO networks were demanding millions of dollars in ransom payments from the company while threatening to release more material.

The alleged hackers published a five-minute video letter to HBO chief Richard Plepler claiming to have “obtained valuable information” in a cyber attack. Cyber criminals said they had stolen 1.5 terabytes of data.

The author of the message dubbed himself “Mr. Smith,” he confirmed his group obtained “highly confidential” documents and data, including scripts, contracts, and personnel files.

According to the website Databreaches.net, on Monday hackers leaked 10 files including what appears to be another script of the fantasy series “Game of Thrones.”

Along with the video letter, the hackers released 3.4GB of files. The dump contained technical data related to the HBO’s internal network and administrator passwords, and of course the draft scripts from five Game of Thrones episodes. The huge trove of files also includes a month’s worth of emails from HBO’s vice president for film programming, Leslie Cohen.

The hackers claim HBO was his 17th victim and that “only 3 of our past targets refused to pay and were punished very badly and 2 of them collapsed entirely.”

HBO fears that hackers will leak other material and that “the forensic review is ongoing.”

“While it has been reported that a number of emails have been made public, the review to date has not given us a reason to believe that our email system as a whole has been compromised,” the statement from the Time Warner unit said. “We continue to work around the clock with outside cybersecurity firms and law enforcement to resolve the incident.”